Non-return valves or check valves have long been known for allowing fluid flow in only one direction. Any reversal of the flow in the undesired direction results in stoppage or checking of the flow. This invention relates to a specific body construction and assembly for a check valve for carrying a fluid flow.
Typical prior art check valve assemblies are comprised of a flow section, a plurality of flappers, a stop tube for controlling the angle of opening of the flappers, and a plurality of vertical supports, commonly referred to as ears, for supporting the stop tube in its proper position. The stop tube is commonly held in place relative to the vertical supports through the use of an external fixation or retention device, such as a pin, or weld deposit about an end of the stop tube where it is inserted into and meets the vertical support.
In many applications, it is desirable to provide a check valve at one or more spaced locations in a pipe line or conduit for handling fluid flows. The check valve assures against back flow and provides a safety margin in the unlikely event of line breakage. These types of check valves, commonly referred to as insert check valves, preferably do not use an external mechanism be used for stop tube retention, thereby allowing for insertion of the check valve within confined space, such as a pipe, or the like.
In addition, in many applications, when a check valve is assembled using external methods to retain the stop tube assembly, heat becomes a factor and may result in the shrinking of the stop tube supports, causing critical deformation.
Hence, there is a need for a check valve including a check valve stop assembly that when retained within a plurality of vertical supports of the check valve flow body provides retention without the use of an external fixation or retention device. In addition, there is a need for a check valve stop assembly that is not susceptible to extreme heat conditions.